This application claims the priority of German Patent Document 101 32 377.8, filed Jul. 6, 2001, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a method for regulating an air-conditioning device having a fresh-air and a circulating-air supply.
EP 0 407 388 B1 describes a method for regulating an air-conditioning device having a fresh-air and a circulating-air supply. The air-conditioning device, which can optionally be operated in the fresh-air and circulating-air mode, has a xe2x80x9ccirculating-air modexe2x80x9d position. The air-conditioning system, after the motor-vehicle engine has been started, is initially operated for a short period in the fresh-air mode, and then the period for the fresh-air mode is prescribed by a timing element.
Similarly, EP 0 023 052 discloses a method for setting the fresh-air/circulating-air flap, in which the internal and external temperatures are determined and, when the external temperature is cooler, switching over to the fresh-air mode takes place for more rapid cooling. The switching is always between the fresh-air or circulating-air mode. However, there is no mixed-air mode.
In contrast, EP 0 825 044 A2 discloses a mixed-air regulating control for a heating/air-conditioning system of a motor vehicle. However, a general regulating control for optimizing the power consumption is described. The external-air and/or circulating-air supply is set in such a manner that the dew point temperature of the spatial air in the vehicle is lower than the temperature on the inside of a vehicle window.
This type of method for the automatic control of the fresh-air/circulating-air flap to increase the cooling power in vehicle heating and air-conditioning systems is disadvantageous in that although fresh air is conducted into the vehicle interior for a prescribed period, after switching over to circulating air the switching-over of the air-conducting means causes a large noise under some circumstances. In addition, the switching-over takes place after a prescribed period and is not matched to the prevailing temperature conditions, such as internal temperature and external temperature.
The object of the invention is to improve the switching of the circulating-air/fresh-air flap in such a manner that a more rapid cooling of the vehicle interior takes place and, in the process, to optimize the noise changes in the vehicle interior.
The object is achieved by the invention described hereinafter.
A substantial advantage of the present invention is that the switching of the fresh air/circulating air takes place as a function of the prevailing temperature conditions outside and within the vehicle. This leads to optimum and rapid cooling of the vehicle, in particular in the case of a hot start with a high air throughput. Cooler air is introduced from the external region into the vehicle interior which does not have to be additionally cooled. In addition, when switching over to full circulating air, the noise irritation is low, because the circulating-air flap has already been partially opened and has not moved from the rest position. The switching-over to circulating air is unnoticeable to the vehicle occupants.